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  <div class="section" id="try-run">
<span id="command:try_run"></span><h1><a class="toc-backref" href="#id1">try_run</a><a class="headerlink" href="#try-run" title="Permalink to this headline">¶</a></h1>
<div class="contents topic" id="contents">
<p class="topic-title">Contents</p>
<ul class="simple">
<li><p><a class="reference internal" href="#try-run" id="id1">try_run</a></p>
<ul>
<li><p><a class="reference internal" href="#try-compiling-and-running-source-files" id="id2">Try Compiling and Running Source Files</a></p></li>
<li><p><a class="reference internal" href="#other-behavior-settings" id="id3">Other Behavior Settings</a></p></li>
<li><p><a class="reference internal" href="#behavior-when-cross-compiling" id="id4">Behavior when Cross Compiling</a></p></li>
</ul>
</li>
</ul>
</div>
<p>Try compiling and then running some code.</p>
<div class="section" id="try-compiling-and-running-source-files">
<h2><a class="toc-backref" href="#id2">Try Compiling and Running Source Files</a><a class="headerlink" href="#try-compiling-and-running-source-files" title="Permalink to this headline">¶</a></h2>
<div class="highlight-cmake notranslate"><div class="highlight"><pre><span></span><span class="nf">try_run(</span><span class="nv">&lt;runResultVar&gt;</span><span class="w"> </span><span class="nv">&lt;compileResultVar&gt;</span><span class="w"></span>
<span class="w">        </span><span class="nv">&lt;bindir&gt;</span><span class="w"> </span><span class="nv">&lt;srcfile&gt;</span><span class="w"> </span><span class="p">[</span><span class="no">CMAKE_FLAGS</span><span class="w"> </span><span class="nv">&lt;flags&gt;...</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">COMPILE_DEFINITIONS</span><span class="w"> </span><span class="nv">&lt;defs&gt;...</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">LINK_OPTIONS</span><span class="w"> </span><span class="nv">&lt;options&gt;...</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">LINK_LIBRARIES</span><span class="w"> </span><span class="nv">&lt;libs&gt;...</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">COMPILE_OUTPUT_VARIABLE</span><span class="w"> </span><span class="nv">&lt;var&gt;</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">RUN_OUTPUT_VARIABLE</span><span class="w"> </span><span class="nv">&lt;var&gt;</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">OUTPUT_VARIABLE</span><span class="w"> </span><span class="nv">&lt;var&gt;</span><span class="p">]</span><span class="w"></span>
<span class="w">        </span><span class="p">[</span><span class="no">ARGS</span><span class="w"> </span><span class="nv">&lt;args&gt;...</span><span class="p">]</span><span class="nf">)</span><span class="w"></span>
</pre></div>
</div>
<p>Try compiling a <code class="docutils literal notranslate"><span class="pre">&lt;srcfile&gt;</span></code>.  Returns <code class="docutils literal notranslate"><span class="pre">TRUE</span></code> or <code class="docutils literal notranslate"><span class="pre">FALSE</span></code> for success
or failure in <code class="docutils literal notranslate"><span class="pre">&lt;compileResultVar&gt;</span></code>.  If the compile succeeded, runs the
executable and returns its exit code in <code class="docutils literal notranslate"><span class="pre">&lt;runResultVar&gt;</span></code>.  If the
executable was built, but failed to run, then <code class="docutils literal notranslate"><span class="pre">&lt;runResultVar&gt;</span></code> will be
set to <code class="docutils literal notranslate"><span class="pre">FAILED_TO_RUN</span></code>.  See the <span class="target" id="index-0-command:try_compile"></span><a class="reference internal" href="try_compile.html#command:try_compile" title="try_compile"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">try_compile()</span></code></a> command for
information on how the test project is constructed to build the source file.</p>
<p>The options are:</p>
<dl>
<dt><code class="docutils literal notranslate"><span class="pre">CMAKE_FLAGS</span> <span class="pre">&lt;flags&gt;...</span></code></dt><dd><p>Specify flags of the form <code class="docutils literal notranslate"><span class="pre">-DVAR:TYPE=VALUE</span></code> to be passed to
the <code class="docutils literal notranslate"><span class="pre">cmake</span></code> command-line used to drive the test build.
The example in <span class="target" id="index-1-command:try_compile"></span><a class="reference internal" href="try_compile.html#command:try_compile" title="try_compile"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">try_compile()</span></code></a> shows how values for variables
<code class="docutils literal notranslate"><span class="pre">INCLUDE_DIRECTORIES</span></code>, <code class="docutils literal notranslate"><span class="pre">LINK_DIRECTORIES</span></code>, and <code class="docutils literal notranslate"><span class="pre">LINK_LIBRARIES</span></code>
are used.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">COMPILE_DEFINITIONS</span> <span class="pre">&lt;defs&gt;...</span></code></dt><dd><p>Specify <code class="docutils literal notranslate"><span class="pre">-Ddefinition</span></code> arguments to pass to <span class="target" id="index-0-command:add_definitions"></span><a class="reference internal" href="add_definitions.html#command:add_definitions" title="add_definitions"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">add_definitions()</span></code></a>
in the generated test project.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">COMPILE_OUTPUT_VARIABLE</span> <span class="pre">&lt;var&gt;</span></code></dt><dd><p>Report the compile step build output in a given variable.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">LINK_LIBRARIES</span> <span class="pre">&lt;libs&gt;...</span></code></dt><dd><p>Specify libraries to be linked in the generated project.
The list of libraries may refer to system libraries and to
<a class="reference internal" href="../manual/cmake-buildsystem.7.html#imported-targets"><span class="std std-ref">Imported Targets</span></a> from the calling project.</p>
<p>If this option is specified, any <code class="docutils literal notranslate"><span class="pre">-DLINK_LIBRARIES=...</span></code> value
given to the <code class="docutils literal notranslate"><span class="pre">CMAKE_FLAGS</span></code> option will be ignored.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">LINK_OPTIONS</span> <span class="pre">&lt;options&gt;...</span></code></dt><dd><p>Specify link step options to pass to <span class="target" id="index-0-command:target_link_options"></span><a class="reference internal" href="target_link_options.html#command:target_link_options" title="target_link_options"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">target_link_options()</span></code></a> in the
generated project.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">OUTPUT_VARIABLE</span> <span class="pre">&lt;var&gt;</span></code></dt><dd><p>Report the compile build output and the output from running the executable
in the given variable.  This option exists for legacy reasons.  Prefer
<code class="docutils literal notranslate"><span class="pre">COMPILE_OUTPUT_VARIABLE</span></code> and <code class="docutils literal notranslate"><span class="pre">RUN_OUTPUT_VARIABLE</span></code> instead.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">RUN_OUTPUT_VARIABLE</span> <span class="pre">&lt;var&gt;</span></code></dt><dd><p>Report the output from running the executable in a given variable.</p>
</dd>
</dl>
</div>
<div class="section" id="other-behavior-settings">
<h2><a class="toc-backref" href="#id3">Other Behavior Settings</a><a class="headerlink" href="#other-behavior-settings" title="Permalink to this headline">¶</a></h2>
<p>Set the <span class="target" id="index-0-variable:CMAKE_TRY_COMPILE_CONFIGURATION"></span><a class="reference internal" href="../variable/CMAKE_TRY_COMPILE_CONFIGURATION.html#variable:CMAKE_TRY_COMPILE_CONFIGURATION" title="CMAKE_TRY_COMPILE_CONFIGURATION"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_TRY_COMPILE_CONFIGURATION</span></code></a> variable to choose
a build configuration.</p>
</div>
<div class="section" id="behavior-when-cross-compiling">
<h2><a class="toc-backref" href="#id4">Behavior when Cross Compiling</a><a class="headerlink" href="#behavior-when-cross-compiling" title="Permalink to this headline">¶</a></h2>
<p>When cross compiling, the executable compiled in the first step
usually cannot be run on the build host.  The <code class="docutils literal notranslate"><span class="pre">try_run</span></code> command checks
the <span class="target" id="index-0-variable:CMAKE_CROSSCOMPILING"></span><a class="reference internal" href="../variable/CMAKE_CROSSCOMPILING.html#variable:CMAKE_CROSSCOMPILING" title="CMAKE_CROSSCOMPILING"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_CROSSCOMPILING</span></code></a> variable to detect whether CMake is in
cross-compiling mode.  If that is the case, it will still try to compile
the executable, but it will not try to run the executable unless the
<span class="target" id="index-0-variable:CMAKE_CROSSCOMPILING_EMULATOR"></span><a class="reference internal" href="../variable/CMAKE_CROSSCOMPILING_EMULATOR.html#variable:CMAKE_CROSSCOMPILING_EMULATOR" title="CMAKE_CROSSCOMPILING_EMULATOR"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_CROSSCOMPILING_EMULATOR</span></code></a> variable is set.  Instead it
will create cache variables which must be filled by the user or by
presetting them in some CMake script file to the values the executable
would have produced if it had been run on its actual target platform.
These cache entries are:</p>
<dl class="simple">
<dt><code class="docutils literal notranslate"><span class="pre">&lt;runResultVar&gt;</span></code></dt><dd><p>Exit code if the executable were to be run on the target platform.</p>
</dd>
<dt><code class="docutils literal notranslate"><span class="pre">&lt;runResultVar&gt;__TRYRUN_OUTPUT</span></code></dt><dd><p>Output from stdout and stderr if the executable were to be run on
the target platform.  This is created only if the
<code class="docutils literal notranslate"><span class="pre">RUN_OUTPUT_VARIABLE</span></code> or <code class="docutils literal notranslate"><span class="pre">OUTPUT_VARIABLE</span></code> option was used.</p>
</dd>
</dl>
<p>In order to make cross compiling your project easier, use <code class="docutils literal notranslate"><span class="pre">try_run</span></code>
only if really required.  If you use <code class="docutils literal notranslate"><span class="pre">try_run</span></code>, use the
<code class="docutils literal notranslate"><span class="pre">RUN_OUTPUT_VARIABLE</span></code> or <code class="docutils literal notranslate"><span class="pre">OUTPUT_VARIABLE</span></code> options only if really
required.  Using them will require that when cross-compiling, the cache
variables will have to be set manually to the output of the executable.
You can also “guard” the calls to <code class="docutils literal notranslate"><span class="pre">try_run</span></code> with an <span class="target" id="index-0-command:if"></span><a class="reference internal" href="if.html#command:if" title="if"><code class="xref cmake cmake-command docutils literal notranslate"><span class="pre">if()</span></code></a>
block checking the <span class="target" id="index-1-variable:CMAKE_CROSSCOMPILING"></span><a class="reference internal" href="../variable/CMAKE_CROSSCOMPILING.html#variable:CMAKE_CROSSCOMPILING" title="CMAKE_CROSSCOMPILING"><code class="xref cmake cmake-variable docutils literal notranslate"><span class="pre">CMAKE_CROSSCOMPILING</span></code></a> variable and
provide an easy-to-preset alternative for this case.</p>
</div>
</div>


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<li><a class="reference internal" href="#">try_run</a><ul>
<li><a class="reference internal" href="#try-compiling-and-running-source-files">Try Compiling and Running Source Files</a></li>
<li><a class="reference internal" href="#other-behavior-settings">Other Behavior Settings</a></li>
<li><a class="reference internal" href="#behavior-when-cross-compiling">Behavior when Cross Compiling</a></li>
</ul>
</li>
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